JP3883050B2 - Dot line printer - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
In the present invention, a hammer mechanism holding a plurality of spring charge type printing hammers arranged side by side in the row direction or circumferential direction is reciprocated along the row direction, and dot rows are printed in the process of this reciprocation. Thus, the present invention relates to a dot line printer for forming characters, figures and the like.
[0002]
[Prior art]
FIG. 2, FIG. 3 and FIG. 4 show the prior art of a dot line printer.
[0003]
In the dot line printer printing method, the hammer mechanism 1 having the printing hammer 2 is reciprocated in the row direction 7 in FIG. 2 by a shuttle mechanism (not shown). In this process, the printing hammer 2 of the hammer mechanism 1 is driven, the striking force of the printing hammer 2 is held by the platen 4, and the printing paper 5 is wound around the platen 4 with a certain incident angle and emission angle. Paper feeding mechanism section 9 that transports the paper in the paper transport direction 8 in the state, the ink ribbon 3 transported in the row direction in a timely manner, and a ribbon separator for preventing printing stains caused by rubbing by the shuttle operation, paper transport operation, and ribbon operation 6, characters, figures and the like are printed on the printing paper 5 in the form of a dot matrix.
[0004]
Usually, in the above dot line printer, the gap between the printing hammer 2 and the platen 4 of the hammer mechanism 1 is managed with an accuracy of 10 μm in order to make the striking force and the time required for striking the printing hammer 2 constant. ing.
[0005]
[Problems to be solved by the invention]
In the prior art, many dot line printers attempt to improve printing speed by arranging the printing hammers 2 in multiple stages in the direction perpendicular to the row direction. In the case of such a dot line printer, in order to overcome the gap amount variation between the printing hammer 2 and the platen 4, the platen 4 has a flat shape. However, as the width of the flat portion of the platen 4 is larger than the printing striking surface 13 with respect to the printing hammers 2 arranged in the direction perpendicular to the row direction, the upward and downward escape from the striking surface 13 of the printing paper 5 is eliminated. As a result, in the process of printing in the line direction, the printing paper 5 is squeezed, and a paper flaw 12 occurs on the printing paper 5 near the end of printing 11 in the line direction. As a result, the printing force is difficult to be transmitted and the problem of printing density occurs. This problem occurs more noticeably on the copy paper (carbon paper, pressure-sensitive paper), and becomes more prominent as the number of copies of the copy paper increases.
[0006]
[Means for Solving the Problems]
In order to solve the above problems, in the present invention, a plurality of printing hammers that are provided with leaf springs and printing pins and are arranged at a predetermined pitch along the printing line direction, and for holding the printing hammers in a non-printing position. Magnet means for generating a magnetic attraction force, and a hammer mechanism for driving the print hammer to demagnetize by supplying a predetermined width release current to a coil provided corresponding to each print hammer to drive the print hammer When the platen print striking face portion for holding the striking force of the printing hammer is flat, Printout sheet I also certain incident angle and exit angle with respect to said platen such as winding around the platen It is attached to the paper feed mechanism that feeds perpendicularly to the line direction in the state, and the hammer mechanism to prevent print stains that are rubbed against each other during paper feed. In the dot line printer having a ribbon separator that, the sheet conveying direction of the width of the print striking face plane portion provided on the platen, the upper and lower both respectively 1.0 or to a plurality of the printing pins of the sheet conveying direction of the width It is characterized by being 1.5 mm larger .
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Next, the present invention will be described with reference to FIG. Since the configuration other than the platen 4 is the same as that of the conventional example, the description thereof is omitted.
[0009]
In the present invention, the flat portion width of the printing portion striking surface 13 of the platen 4 is determined with respect to the arrangement range of the printing hammer pins in the vertical direction in a direction parallel to the row direction of the printing hammer 2. Affects the shading width (printing deviation) of printing. Therefore, by reducing the range in the printing paper direction as much as possible, there is an effect of providing the relief 10 of the printing paper 5 at the upper and lower portions of the arrangement range of the printing hammers 2.
[0010]
Here, FIG. 5 is a graph showing the average print shading width on copy paper. The horizontal axis of the graph of FIG. 5 shows the flat part width of the platen on the copy paper (the vertical width from the arrangement range in the direction perpendicular to the line direction of the printing hammer), and the vertical width is 1 to 3 mm, respectively. This is what I tried about. According to this measurement result, the width of the print density increases from 1 mm to 1.5 mm, and rapidly increases from 1.5 mm or more. It can be seen that the shade width does not increase at 1 mm.
[0011]
Accordingly, by reducing the width of the flat part of the platen to within 1.5 mm above and below, paper flaws diverge in the relief 10 and even if the print paper 5 is squeezed in the line direction during the printing process, the paper flaws are generated. It can be avoided. Furthermore, by setting the flat portion width to about 1 mm in each of the upper and lower sides, it is possible to more effectively avoid the occurrence of paper wrinkles.
[0012]
Accordingly, the flat sheet width of the conventional platen 4 is larger than the printing striking surface 13, so that the printing paper 5 does not escape upward and downward with respect to the striking surface 13, and the printing paper 5 is ladder in the process of printing in the line direction. In the vicinity of the end of printing 11 in the line direction, the paper sheet 12 is generated on the printing paper 5 and the printing paper 5 is lifted from the striking surface 13 of the platen 4, so that the printing force is difficult to be transmitted and there is a problem of printing shading. It became possible to solve the occurrence of
[0013]
【The invention's effect】
As described above in detail, according to the present invention, the width of the flat portion of the platen for maintaining the striking force of the printing hammer is set to 1.0 respectively in the vertical direction from the arrangement range in the direction perpendicular to the row direction of the printing hammer. or by 1.5mm larger to Rukoto to avoid paper wrinkles generated by being rubbed in the row direction in the printing paper is the printing process, i.e., can solve the print shading problems.
[Brief description of the drawings]
FIG. 1 is a transverse sectional view around a printing hammer showing an example of the present invention.
FIG. 2 is a perspective view of a dot line printer showing the prior art.
FIG. 3 is a transverse cross-sectional view around a printing hammer showing the prior art.
FIG. 4 is a top cross-sectional view around a printing hammer showing the occurrence of paper flaws in the prior art.
FIG. 5 is a graph showing the print shading width on copy paper.
[Explanation of symbols]
1 is a hammer mechanism, 2 is a printing hammer, 3 is an ink ribbon, 4 is a platen, 5 is printing paper, 6 is a ribbon separator, 7 is a reciprocating direction of the hammer mechanism, 8 is a paper transport direction, and 9 is a paper feeding mechanism. , 10 is the escape of printing paper, 11 is near the end of printing in the line direction, 12 is a paper bag, and 13 is a printing striking surface.

Claims (1)

A plurality of printing hammers, each having a leaf spring and a printing pin, arranged at a predetermined pitch along the printing line direction; and magnet means for generating a magnetic attraction force to hold the printing hammer in a non-printing position; In order to maintain the striking force of the printing hammer, a hammer mechanism that demagnetizes and drives the printing hammer by supplying a predetermined width release current to the coil provided corresponding to each printing hammer to drive the printing hammer a print striking face portion plane of the platen and, fixed angle of incidence and Printout sheet I also exit angle is sent to the row direction and vertical in the state as winding around the platen paper feed mechanism with respect to the platen In order to prevent print smears that occur on the printing paper due to rubbing with the paper feeding section, the dot mechanism is attached to the hammer mechanism and has a ribbon separator provided between the ink ribbon and the printing paper. In the down printer,
Wherein the sheet conveyance direction of the width of the print striking face plane portion provided on the platen, and large vertical co respectively 1.0 to 1.5mm for a plurality of the sheet conveying direction of the width of the printing pins Dot line printer.

Images